Meaning of acharya - realizations and comments on guru-tattva

In another thread devotees are commenting about different kind of gurus.From my personal experience it took me a while to actually find a Guru.I think that mainly person has to live some time with Guru to actually see if He or She is for him.Otherways,how can we know? Maybe that superbonafide guru smokes bidi when nobody sees him,or has illicit activities on a daily basis like some past Iskcon gurus.There is a excellent little book by Srila Ananta das Babaji Maharaja-Guru Tattva Vijnana.
Also, not to forget Ramdas prabhu mentions difference of explanation about the use of name Acharya? When and who is actually using that term?Who is Acharya?

In the literal sense of the word, acarya refers to a spiritual teacher who knows and teaches acara, that is, proper conduct according to the scriptures.

What does Ramdas say about the word? (links please)

In the Bhagavata, the word is used in a general sense, referring to a spiritual master. Bhagavata 11.29.6:

naivopayanty apacitiM kavayas taveza
brahmAyuSApi kRtam Rddha-mudaH smarantaH
yo ’ntar bahis tanu-bhRtAm azubhaM vidhunvann
AcArya-caittya-vapuSA sva-gatiM vyanakti
O Lord! The poets are unable to express their gratitude for You even if they had a lifetime as long as that of Brahma. With great joy they remember you as the one who is both within and without the embodied souls, dissipating their inauspiciousness in the forms of the acarya and the caittya-guru (supersoul), thus showing them the path to follow.

I am not aware of specific protocol for the usage of the term, one of its being received only for a certain class of gurus (like those born in Nityananda-vamsa or Advaita-vamsa). Any thoughts, pandits out there?